UPS spokesman Steve Gaut told The Associated Press that an employee fired inside the facility before the drivers were sent out to do their normal daily deliveries. Gaut said four people were injured and that he believed the shooter "turned the gun on himself."

Gaut did not have immediate information about anyone's condition. Nor did Brent Andrew, spokesman for Zuckerberg San Francisco General Hospital, which had received the victims. He did not know exactly how many people.

Auto shop owner Robert Kim said he heard about five to eight rapid gunshots. The next thing he knew, he said, "a mob of UPS drivers" was running down the street screaming "shooter, shooter."